Studies of the physiological properties of freshly isolated smooth muscle cells from the stomach of Bufo marinus are proposed. Insight into the mechanism of force generation will be obtained by measurement of the mechanical response to sudden changes in length. Studies of the arrangement of elements of the contractile machinery will be obtained using fluorescent probes of the proteins involved in force generation. Membrane properties will be probed by voltage-clamp techniques. Membrane transport processes will be investigated by ion flux studies and ion gradients measured with ion selective electrodes.